/**
 * @Author: Lenovo
 * @Date: 2024/7/19 16:00
 * @description:
 */
public class BinaryTree {
    static class TreeNode{
        public char val;
        public TreeNode left;
        public TreeNode right;

        public TreeNode(char val) {
            this.val = val;
        }
    }
    public TreeNode createTree(){
        TreeNode A = new TreeNode('A');
        TreeNode B = new TreeNode('B');
        TreeNode C = new TreeNode('C');
        TreeNode D = new TreeNode('D');
        TreeNode E = new TreeNode('E');
        TreeNode F = new TreeNode('F');
        TreeNode G = new TreeNode('G');
        TreeNode H = new TreeNode('H');
        A.left = B;
        A.right = C;
        B.left = D;
        B.right = E;
        C.left = F;
        C.right = G;
        E.right = H;
        return A;
    }
    // 获取树中节点的个数
    public static int nodeSize;
    public void size(TreeNode root){
        if (root == null) {
            return;
        }
        nodeSize++;
        size(root.left);
        size(root.right);
    }
    // 子问题：树的节点 = 左子树的结点 + 右子树的节点 + 1
    public int size2(TreeNode root){
        if (root == null){
            return 0;
        }
        return size2(root.left) + size2(root.right) + 1;
    }
    // 获取叶子节点的个数
    public static int leafNode;
    public void getLeafNodeCount(TreeNode root){
        if (root == null){
            return;
        }
        if (root.left == null && root.right == null){
            leafNode++;
        }
        getLeafNodeCount(root.left);
        getLeafNodeCount(root.right);

    }
    //子问题
    public int getLeafNodeCount2(TreeNode root){
        if (root == null){
            return 0;
        }
        if (root.left == null && root.right == null){
            return 1;
        }
        return getLeafNodeCount2(root.left)+getLeafNodeCount2(root.right);

    }
    // 子问题思路-求叶子结点个数
    // 获取第K层节点的个数
    public int getKLevelNodeCount(TreeNode root,int k){
        if (root == null){
            return 0;
        }
        if (k == 1){
            return 1;
        }
        return getKLevelNodeCount(root.left,k-1)+getKLevelNodeCount(root.right,k-1);
    }
    // 获取二叉树的高度
    public int getHeight(TreeNode root){
         if (root == null){
             return 0;
         }
         int leftHight = getHeight(root.left);
         int rightHight = getHeight(root.right);
         return Math.max(leftHight,rightHight)+1;

    }
    // 检测值为value的元素是否存在
    public TreeNode find(TreeNode root, int val){
        if (root == null) {
            return null;
        }if (root.val == val){
            return root;
        }
        TreeNode leftNode = find(root.left,val);
        if (leftNode != null){
            return leftNode;
        }
        TreeNode rightNode = find(root.right,val);
        if (rightNode != null){
            return rightNode;
        }
        return null;
    }
    //层序遍历
    public void levelOrder(TreeNode root){

    }
    // 判断一棵树是不是完全二叉树
    public boolean isCompleteTree(TreeNode root){
        return false;
    }
    // 前序遍历
    public void preOrder(TreeNode root){
        if (root == null){
            return;
        }
        // 打印根节点
        System.out.print(root.val+" ");
        //左节点
        preOrder(root.left);
        //右节点
        preOrder(root.right);
    }
    // 中序遍历
    public void inOrder(TreeNode root){
        if (root == null) {
            return;
        }
        //左节点
        inOrder(root.left);
        // 打印根节点
        System.out.print(root.val+" ");
        //右节点
        inOrder(root.right);
    }
    // 后序遍历
    public void postOrder(TreeNode root){
        if (root == null){
            return;
        }
        //左节点
        postOrder(root.left);
        //右节点
        postOrder(root.right);
        // 打印根节点
        System.out.print(root.val+" ");
    }

}
